1. Field of the Invention
The present invention relates to a driving method of a printer apparatus to mix and discharge a quantitative and a discharge medium, more particularly, to the driving method of the printer apparatus that is possible to surely the mixing and the discharge actuation by regulating timing the mixing and the discharge actuation of the quantitative and the discharge medium.
2. Description of the Related Art
Recently, document creating by using a computer called desktop publishing has become popular particularly at office, at present the request to output not only letters and figures but also color national images such as pictures with the letters and figures has increased. With this, it has been requested to print the high grade national images and gradation representation by intermediate representation has been important.
As so-called an on-demand type printer apparatus which discharges a drop of ink from a nozzle only when it is necessary to print according to a control signal corresponding to a recording signal, adheres it to a recorded material such as a paper and a film and records has a potential of a small size and low cost, it has recently been spreading.
Though various methods have been proposed as the methods for discharge the drop of ink from the nozzle, the method for using piezoelectric or exoergic elements is usual. The former is the method for discharge by applying pressure to the ink by deforming the piezoelectric elements. The latter is the method for discharge the ink by the pressure of bubble generated by heating and evaporating the ink by the exoergic elements.
As the method for executing pseudoly the gradation representation by the intermediate display by the on-demand type printer apparatus for getting the the drop of ink, various methods have been proposed. That is to say, as a first method, the method for controlling the size of the drop of ink discharge by changing voltage and a pulse width of a voltage pulse applied to the piezoelectric or the exoergic elements and representing gradation as a radius of the printing dot is variable is given.
However, in the first method, as the it is stopped to discharge the ink when the voltage and the pulse width to the piezoelectric or the exoergic elements are too reduced, there are disadvantages that the minimum radius of the drop of ink is limited, there is few the number of representable gradation steps and it is particularly very hard to represent a picture of low concentration. Therefore, it is unsatisfied to print out the national image.
As a second method, the method for forming by a matrix that, for example, a picture element is formed by 4.times.4 dots without changing the radius of the dot and for executing the gradation representation by a matrix unit by using the dither method is given.
However, in the second method, though it is possible to represent the concentration of 17 gradations when a picture element is formed by 4.times.4 matrix, in case of printing by using, for example, the same dot density as that of the first method, resolution is degraded to one fourth, roughness is remarkable, therefore, it is unsatisfied to print out the national image.
The inventors and so on of the present invention have proposed a two fluids mixing type printer apparatus that a diluent fluid that discharges at once the diluent ink which is made by mixing the ink and the diluent fluid of a transparent solvent at the fixed mixing rate just before discharge and records by adhering it on the recorded material as shown in, for example, Special Disclosed Patent Bulletin No. Hei 5-201024 for making clear principally problems of the conventional on-demand type printer apparatus which discharges only the ink. Of the methods, the method which records by discharge the discharge medium as the ink is the quantitative medium, the diluent fluid is the discharge medium, and the ink of the quantitative medium is the diluent ink by mixing with the diluent fluid of the discharge medium is called the carrier discharge method, however, in the printer apparatus, it is no problem even if the diluent fluid is the quantitative medium and the ink is the discharge medium.
In the printer apparatus of the carrier discharge method, it is possible to control the concentration of the drop of the discharged diluent ink, to change the concentration per dot printed, and to print out the national images that the intermediate gradation is rich without generating degradation of the resolution.
As the two fluids mixing type printer apparatus, the printer is given that includes a first pressure room into which the quantitative medium, a second pressure room into which the discharge medium is introduced, a first nozzle communicated with the first pressure room and a second nozzle communicated with the second pressure room which are opened side by side, makes the quantitative medium leak out from the first nozzle through a nozzle opening surface to the second nozzle, contacts with the discharge medium filled in the neighborhood of the end of the second nozzle, and discharges the quantitative and the discharge medium as the mixed solution by discharge the discharge medium of the fixed quantity from the second nozzle. That is to say, in this printer, the gradation is represented by changing the concentration of the ink of the drop of the mixed fluid per dot by mixing with the diluent fluid or the ink which is the discharge medium of the fixed quantity by changing the fixed quantity of the ink or diluent which is the quantitative medium.
The printer apparatus includes a first pressure applying means which applies pressure to the quantitative medium in the first pressure room and a second pressure applying means which applies the pressure to the discharge medium in the second pressure room, makes the quantitative medium leak out from the first nozzle communicated with the quantitative medium by applying the pressure to the quantitative medium in the first pressure room by the first pressure applying means, and makes the getting medium leak out from the second nozzle communicated with the discharge medium by applying the pressure to the discharge medium in the second pressure room by the second pressure applying means.
As the first and second pressure applying means, piezoelectric elements and so on are given to be expanded and constricted by changing driving voltage, to apply the pressure to the first and the second pressure rooms and to apply the pressure to the quantitative medium and the discharge medium filled in them. In the pressure applying means, quantity and so on of the quantitative medium leaked to the first nozzle by the pulse width and so on are regulated.
Actuation of the printer is regulated by timing of changing the driving voltage of the first and the second pressure applying means is regulated. That is to say, if the actuation to push out the quantitative medium from the first nozzle to the second nozzle by changing the driving voltage of the first pressure applying means from a stationary state to the fixed voltage and the actuation to push out the quantitative medium with the discharging medium from the second nozzle by changing the driving voltage of the second pressure applying means from the stationary state to the fixed voltage is not executed at proper timing, it is impossible to form the dot of the accurate concentration of the ink.
For example, when changing the driving voltage of the second pressure applying means and discharge the discharge medium before the quantitative medium leaked from the first nozzle is contacted with the discharge medium in the neighborhood of the end of the second nozzle, it is easily impossible to mix all of the fixed quantity of the quantitative medium with the discharge medium and to form the dot of the accurate concentration of the ink. Further, the unmixed quantitative medium remains on the opening surface of the nozzle, and it causes inconvenience to be mixed with the mixed drop of fluid of next time and so on.